If you hit only murderers, you create the right incentives in the group the terrorists pretend to speak for - that becoming a murderer is dangerous, while not being one is safe. But if you take the easy way out of the aim problem and just target the whole demographic group wholesale, then you hit 9 innocents for every murderer you hit, and they all have relatives. So you recruit more new murderers than you kill old ones. The size of the terrorist group, of the hard liners not the whole demographic, goes up.
The key is to focus on the size of the radicalized, committed group, including their recruitment. Aim, discrimination between those who are really your enemies and those who are not, is the all important thing.
That should be chiseled in granite!